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The present study assessed the possible interaction of saponins with the phenolic antinutritional factor tannin and the animal-origin diet component, cholesterol, in the context of plant-based aquafeed formulation with the addition of cholesterol. An in vitro analysis evaluated the ability of saponin to neutralize cholesterol and tannin. The results revealed that the neutralizing capacity of cholesterol and tannin at 0.5% saponin concentration was 49.84% and 40.32%, respectively. In the second experiment, a feeding trial was conducted for 45 days in Labeo rohita fingerlings. Twelve fish each (average weight 5.28 ± 0.34 g) were randomly distributed into six treatment groups in triplicates. Six iso-nitrogenous (30% CP) and isolipidic (6%) purified diets were prepared: control (C), saponin (CS; C + 0.5% saponin), cholesterol (CC; C + 1% cholesterol), tannin (CT; C + 1.25% tannin), saponin and cholesterol (SC; C + 0.5% saponin and 1% cholesterol), and saponin and tannin (ST; C + 0.5% saponin and 1.25% tannin). The group fed 0.5% saponin and 1% cholesterol showed the maximum weight gain (%), specific growth rate, and protein efficiency ratio with the lowest FCR value, which was similar (P > 0.05) to the control. The addition of tannin (1.25%) to the saponin (0.5%) containing diet (ST group) partially restored growth performance. The HSI value significantly increased due to the feeding of saponin but decreased in the SC and ST groups compared to the saponin-fed (CS) group. The blood parameters like hemoglobin content, RBC, and leucocyte counts were higher (P < 0.05) in the SC and ST groups compared to the CS group, although significantly (P < 0.05) lower than that of the control (C) group. Serum total protein, albumin, and globulin values in the CS group decreased but improved in the SC and ST groups. Serum transaminase enzymes (SGPT, SGOT), total bilirubin, and creatinine were increased in the saponin-fed CS group but reduced in the SC and ST groups. In conclusion, saponins had an unambiguous interaction with tannin and cholesterol in both in-vitro and in-vivo conditions. Further, adding (1%) cholesterol into saponin (0.5%) containing aqua-feeds can negate the effect of saponin. [ABSTRACT FROM AUTHOR]

Asian catfish, Clarias magur (Hamilton, 1822), known as magur, is a popular food fish in Asian countries because of its high nutritional and medicinal value. Aquaculture of magur is constrained by non‐availability of seed due to very high mortality during the early larval stages. The strategies to enhance the larval survival during the early stages could be a major step in enhancing the seed production of this species. So, the aim of the present study was to assess the effect of highly unsaturated fatty acids (HUFA)‐ and vitamin C‐enriched infusoria on the growth and survival of C. magur larvae. Eight‐day‐old larvae with an average weight of 3 mg and length of 5 mm were stocked in plastic crates (30 x 20 x 18 cm) each containing 40 litres of water. A total of 16 crates were used in experiment and in each crate 100 larvae were stocked. The larvae were fed three times daily with HUFA, vitamin C, both HUFA and vitamin C and un‐enriched infusoria @ 9–10 numbers per ml of rearing water for 30 days in four different treatment groups. The proximate analysis of different enriched and un‐enriched infusoria showed the highest (84.25%) moisture content in HUFA‐enriched Infusoria, and the highest percentage of crude protein (9.80%), crude lipid (3.50%) and ash content (0.78%) in vitamin C‐enriched Infusoria. The survivability analysis showed the highest survival in the treatment group fed with HUFA‐enriched infusoria (49.25%) and the lowest in the control group (18.25%). This indicates that the enrichment of infusoria with HUFA could increase the survival rate significantly. The highest body weight gain (55.75 mg) was observed in HUFA‐enriched group but not significantly different from the control group. The study indicates that the enrichment of infusoria with HUFA have a significant influence on larval survival. [ABSTRACT FROM AUTHOR]

The availability of zinc has been correlated with reproductive performance. To validate the hypothesis, a 60‐day feeding trial was conducted to evaluate the effect of dietary zinc on reproductive performance and gonadotropin gene (FSH and LH) expression in threatened Clarias magur brooder. Four isonitrogenous (35%) and iso‐energetic (372.18 ± 1.73 k cal/100 g) diets were prepared with zinc acetate as control (100 mg/kg diet normal requirement), T1 (50 mg/kg diet, low zinc), T2 (200 mg/kg diet, medium zinc) and T3 (300 mg/kg diet, high zinc). The weight gain % and specific growth rate were significantly (p < 0.05) decreased with the increased dietary zinc level. The pituitary mRNA levels of FSH were assessed during the reproductive cycle of female C. magur, and the FSH expression was increased which was significantly (p < 0.05) highest in T1 group. Similarly, LH expression was revealed to be highest. In all treatment groups except T1, GTH expression reduced significantly by increasing zinc inclusion in the diet. GSI and fecundity were lowest during initial sampling and start to increase was observed. The highest GSI and fecundity were recorded in the T1; however, GSI and fecundity significantly (p < 0.05) reduced with increasing the zinc level. Reproductive parameters like spawning fecundity, fertilization rate, hatching rate and larval survival were found to be dose‐dependent of zinc. This revealed that 50 mg/kg zinc was optimum for enhanced reproductive performance; therefore, the present study proposed that 50 mg/kg of zinc could be supplemented for flexible enhanced reproductive performance in threatened Asian catfish, C. magur. [ABSTRACT FROM AUTHOR]

A 60-days feeding trial was conducted to evaluate the effects of different protein and carbohydrate ratios in the diet of Magur (Clarias magur) fingerling (Average weight 3.26±0.17 - 3.61±0.19 g). Six hetero-nitrogenous (150 - 400 g kg-1 crude protein (CP) and iso-energetic (19.0 -19.8 MJ kg-1 GE, gross energy) diets such as D1 (0 g kg-1 Starch and 40% CP), D2 (100 g kg-1 Starch, 35% protein), D3 (200 g kg-1 Starch, 30% CP), D4 (300 g kg-1 Starch, 25% CP), D5 (400 g kg-1 Starch, 20% CP) and D6 (500 g kg-1 Starch, 15% CP), were prepared and fed at 5% of body weight. Growth parameters; i.e. The weight gain, percent weight gain, SGR, among all the groups were decreasing significantly (P<0.05) from the highest protein to lowest protein fed group except D1 and D2 groups, simultaneously FCR found increasing. PER was highest in D6 (3.10), followed by D5 (2.88), D4 (2.49), D3 (2.32) D2 (2.17) and lowest in D1 (1.95). A cent percent survival was achieved in all the experimental groups. The activity of amylase has shown an increasing trend with increasing in carbohydrate levels while protease activity shown a decreasing trend on successive increase in carbohydrate levels. Lipase activity was significantly (P<0.05) increased in the groups with more than 60% starch inclusion in a dose-dependent manner. The study concluded that the C.magur can utilise carbohydrate up to 67%, however, it compromises growth and increased FCR. The significantly highest (P<0.05) protein deposition observed in the D2 diet (35% CP). Therefore 35% crude protein can be acceptable with 44% inclusion of carbohydrate. Thus the study suggests that ratio of protein and carbohydrate as 1:1.26 given optimum growth and better utilization of nutrients. [ABSTRACT FROM AUTHOR]

The enhancement of both disease resistance and growth performance are essential for successful fish production and the use of dietary medicinal herbs can be used as natural immunostimulants as well as growth promoter in fish. Consequently, a 45-day feeding experiment was conducted to explore the effect of dietary blue lotus (Nymphaea nouchali) leaf (BLL) and blue lotus flower (BLF) on growth and haemato-immunological parameters in Labeo rohita fingerlings and reported for the first time. Two hundred fingerlings (average weight 18.5 ± 0.1 g) were randomly assigned to five treatment groups in quadruplicate. Five purified diets (35% CP) were made with varying degrees of either blue lotus leaf (BLL) or flower (BLF) inclusion viz.T1 (Control - 0%), T2 (0.2% BLL), T3 (0.4% BLL), T4 (0.2% BLF) and T5 (0.4% BLF). Weight gain (percent) and SGR increased significantly (P < 0.05) after inclusion at graded levels, but other measures such as FCR, PER, HSI, and GSI showed no discernible changes (P > 0.05). Total protein, globulin, and glucose concentrations in the serum showed a significant difference (P < 0.05). Serum total protein and globulin levels were significantly (P < 0.05) higher in the T5 group, whereas serum glucose levels, declined significantly (P < 0.05) compared to contol. There was a significant (P < 0.05) rise in WBC count, but no significant (P > 0.05) changes in haemoglobin (Hb) and RBC count. Overall, the findings of the results conclude that the dietary supplementation of blue lotus leaves and flowers can increase growth and enhance better immune response in Indian major carp, L. rohita juveniles. • Dietary blue lotus (Nymphaea nouchali) flower (BLF) or leaf (BLL) promoted growth performance of Labeo rohita. • BLF or BLL showed hypoglycemic response. • BLF or BLL boosted immune response in Labeo rohita. [ABSTRACT FROM AUTHOR]

Carotenoprotein, a complex of carotenoids and protein, extracted from shrimp shell waste can be an effective source of carotenoid as well as antioxidant in fish diets. In the present study, the nutritional potential of carotenoprotein extracted from shell wastes of Parapeneopsis stylifera on growth, physiometabolic changes and coloration in high-value ornamental fish, oscar (Astronotus ocellatus) was assessed in a 120 days feeding trial. Four iso‑nitrogenous (30–31% CP) and isolipidic (11.34–11.55% CL) diets were formulated with graded levels of carotenoprotein inclusion like 0%, 5%, 10% and 15% and designated as Control, T1, T2 and T3 respectively. At the end of the feeding trial, growth indices such as final body weight, weight gain, and specific growth rate indicated that fish fed with 10 and 15% levels of carotenoprotein incorporated diet showed higher growth compared to control and T1. Oxidative stress enzymes like SOD and Catalase were lower in 15% and 10% carotenoprotein incorporated diets respectively in both gills and liver. Stress indicators like serum glucose and cortisol activity were found to be higher in control than in diets with 10% (T2) as well as 15% (T3), suggesting the stress-reducing ability of the carotenoprotein in fish feed. Relatively higher respiratory burst activity in fishes of T3 group indicated higher immunity status of the fish. Quantitative colour values in terms of redness, chroma in the fin region as well as carotenoid content in scale, skin and muscle of fish were higher in T2 (10% carotenoprotein incorporated diet) as compared to T3 (15% carotenoprotein incorporated diet). Overall, this study clearly showed that dietary incorporation of as little as 10% carotenoprotein is advisable to ornamental fish farmers for enhanced growth, colouration, as well as antioxidant activity in this popular high value ornamental fish for maximizing their profit. • Dietary supplementation of shrimp carotenoprotein on ornamental fish was studied. • Improved growth, better feed utilization and antioxidant activity observed. • Higher level of carotenoprotein up to 10% significantly improved the immune status. • Instrumental L*, a*, b* values, chroma, hue angle was superior in 10% inclusion level. • Inclusion of carotenoprotein is cost effective as evaluated by BCR against their costs. [ABSTRACT FROM AUTHOR]